Matthew Pickering pushed to branch wip/t29090 at Glasgow Haskell Compiler / GHC Commits: 4bc78496 by Sebastian Graf at 2025-07-24T16:19:34-04:00 CprAnal: Detect recursive newtypes (#25944) While `cprTransformDataConWork` handles recursive data con workers, it did not detect the case when a newtype is responsible for the recursion. This is now detected in the `Cast` case of `cprAnal`. The same reproducer made it clear that `isRecDataCon` lacked congruent handling for `AppTy` and `CastTy`, now fixed. Furthermore, the new repro case T25944 triggered this bug via an infinite loop in `cprFix`, caused by the infelicity in `isRecDataCon`. While it should be much less likely to trigger such an infinite loop now that `isRecDataCon` has been fixed, I made sure to abort the loop after 10 iterations and emitting a warning instead. Fixes #25944. - - - - - 0a583689 by Sylvain Henry at 2025-07-24T16:20:26-04:00 STM: don't create a transaction in the rhs of catchRetry# (#26028) We don't need to create a transaction for the rhs of (catchRetry#) because contrary to the lhs we don't need to abort it on retry. Moreover it is particularly harmful if we have code such as (#26028): let cN = readTVar vN >> retry tree = c1 `orElse` (c2 `orElse` (c3 `orElse` ...)) atomically tree Because it will stack transactions for the rhss and the read-sets of all the transactions will be iteratively merged in O(n^2) after the execution of the most nested retry. - - - - - a49eca26 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Renaming around predicate types .. we were (as it turned out) abstracting over type-class selectors in SPECIALISATION rules! Wibble isEqPred - - - - - f80375dd by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Refactor of Specialise.hs This patch just tidies up `specHeader` a bit, removing one of its many results, and adding some comments. No change in behaviour. Also add a few more `HasDebugCallStack` contexts. - - - - - 1bd12371 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Improve treatment of SPECIALISE pragmas -- again! This MR does another major refactor of the way that SPECIALISE pragmas work, to fix #26115, #26116, #26117. * We now /always/ solve forall-constraints in an all-or-nothing way. See Note [Solving a Wanted forall-constraint] in GHC.Tc.Solver.Solve This means we might have unsolved quantified constraints, which need to be reported. See `inert_insts` in `getUnsolvedInerts`. * I refactored the short-cut solver for type classes to work by recursively calling the solver rather than by having a little baby solver that kept being not clever enough. See Note [Shortcut solving] in GHC.Tc.Solver.Dict * I totally rewrote the desugaring of SPECIALISE pragmas, again. The new story is in Note [Desugaring new-form SPECIALISE pragmas] in GHC.HsToCore.Binds Both old-form and new-form SPECIALISE pragmas now route through the same function `dsSpec_help`. The tricky function `decomposeRuleLhs` is now used only for user-written RULES, not for SPECIALISE pragmas. * I improved `solveOneFromTheOther` to account for rewriter sets. Previously it would solve a non-rewritten dict from a rewritten one. For equalities we were already dealing with this, in Some incidental refactoring * A small refactor: `ebv_tcvs` in `EvBindsBar` now has a list of coercions, rather than a set of tyvars. We just delay taking the free vars. * GHC.Core.FVs.exprFVs now returns /all/ free vars. Use `exprLocalFVs` for Local vars. Reason: I wanted another variant for /evidence/ variables. * Ues `EvId` in preference to `EvVar`. (Evidence variables are always Ids.) Rename `isEvVar` to `isEvId`. * I moved `inert_safehask` out of `InertCans` and into `InertSet` where it more properly belongs. Compiler-perf changes: * There was a palpable bug (#26117) which this MR fixes in newWantedEvVar, which bypassed all the subtle overlapping-Given and shortcutting logic. (See the new `newWantedEvVar`.) Fixing this but leads to extra dictionary bindings; they are optimised away quickly but they made CoOpt_Read allocate 3.6% more. * Hpapily T15164 improves. * The net compiler-allocation change is 0.0% Metric Decrease: T15164 Metric Increase: CoOpt_Read T12425 - - - - - 953fd8f1 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Solve forall-constraints immediately, or not at all This MR refactors the constraint solver to solve forall-constraints immediately, rather than emitting an implication constraint to be solved later. The most immediate motivation was that when solving quantified constraints in SPECIALISE pragmas, we really really don't want to leave behind half- solved implications. Also it's in tune with the approach of the new short-cut solver, which recursively invokes the solver. It /also/ saves quite a bit of plumbing; e.g - The `wl_implics` field of `WorkList` is gone, - The types of `solveSimpleWanteds` and friends are simplified. - An EvFun contains binding, rather than an EvBindsVar ref-cell that will in the future contain bindings. That makes `evVarsOfTerm` simpler. Much nicer. It also improves error messages a bit. All described in Note [Solving a Wanted forall-constraint] in GHC.Tc.Solver.Solve. One tiresome point: in the tricky case of `inferConstraintsCoerceBased` we make a forall-constraint. This we /do/ want to partially solve, so we can infer a suitable context. (I'd be quite happy to force the user to write a context, bt I don't want to change behavior.) So we want to generate an /implication/ constraint in `emitPredSpecConstraints` rather than a /forall-constraint/ as we were doing before. Discussed in (WFA3) of the above Note. Incidental refactoring * `GHC.Tc.Deriv.Infer.inferConstraints` was consulting the state monad for the DerivEnv that the caller had just consulted. Nicer to pass it as an argument I think, so I have done that. No change in behaviour. - - - - - 6921ab42 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Remove duplicated code in Ast.hs for evTermFreeVars This is just a tidy up. - - - - - 1165f587 by Simon Peyton Jones at 2025-07-25T09:49:58+01:00 Small tc-tracing changes only - - - - - 0776ffe0 by Simon Hengel at 2025-07-26T04:54:20-04:00 Respect `-fdiagnostics-as-json` for core diagnostics (see #24113) - - - - - cc1116e0 by Andrew Lelechenko at 2025-07-26T04:55:01-04:00 docs: add since pragma to Data.List.NonEmpty.mapMaybe - - - - - ee2dc248 by Simon Hengel at 2025-07-31T06:25:35-04:00 Update comments on `OptKind` to reflect the code reality - - - - - b029633a by Wen Kokke at 2025-07-31T06:26:21-04:00 rts: Disable --eventlog-flush-interval unless compiled with -threaded. This commit fixes issue #26222: Using --eventlog-flush-interval with the non-threaded RTS leads to eventlog corruption. https://gitlab.haskell.org/ghc/ghc/-/issues/26222 This commit makes three changes when code is compiled against the non-threaded RTS: 1. It disables the --eventlog-flush-interval flag. 2. It disables the documentation for the --eventlog-flush-interval flag. 3. It disables the relevant state from RtsConfig and code from Timer. 4. It updates the entry for --eventlog-flush-interval in the users guide. - - - - - 31159f1d by Wen Kokke at 2025-07-31T06:26:21-04:00 rts: Split T20006 into tests with and without -threaded - - - - - 618687ef by Simon Hengel at 2025-07-31T06:27:03-04:00 docs/users_guide/win32-dlls.rst: Remove references to `readline` - - - - - 083e40f1 by Rodrigo Mesquita at 2025-08-01T04:38:23-04:00 debugger: Uniquely identify breakpoints by internal id Since b85b11994e0130ff2401dd4bbdf52330e0bcf776 (support inlining breakpoints), a breakpoint has been identified at runtime by *two* pairs of . - The first, aka a 'BreakpointId', uniquely identifies a breakpoint in the source of a module by using the Tick index. A Tick index can index into ModBreaks.modBreaks_xxx to fetch source-level information about where that tick originated. - When a user specifies e.g. a line breakpoint using :break, we'll reverse engineer what a Tick index for that line - We update the `BreakArray` of that module (got from the LoaderState) at that tick index to `breakOn`. - A BCO we can stop at is headed by a BRK_FUN instruction. This instruction stores in an operand the `tick index` it is associated to. We look it up in the associated `BreakArray` (also an operand) and check wheter it was set to `breakOn`. - The second, aka the `ibi_info_mod` + `ibi_info_ix` of the `InternalBreakpointId`, uniquely index into the `imodBreaks_breakInfo` -- the information we gathered during code generation about the existing breakpoint *ocurrences*. - Note that with optimisation there may be many occurrences of the same source-tick-breakpoint across different modules. The `ibi_info_ix` is unique per occurrence, but the `bi_tick_ix` may be shared. See Note [Breakpoint identifiers] about this. - Note that besides the tick ids, info ids are also stored in `BRK_FUN` so the break handler can refer to the associated `CgBreakInfo`. In light of that, the driving changes come from the desire to have the info_id uniquely identify the breakpoint at runtime, and the source tick id being derived from it: - An InternalBreakpointId should uniquely identify a breakpoint just from the code-generation identifiers of `ibi_info_ix` and `ibi_info_mod`. So we drop `ibi_tick_mod` and `ibi_tick_ix`. - A BRK_FUN instruction need only record the "internal breakpoint id", not the tick-level id. So we drop the tick mod and tick index operands. - A BreakArray should be indexed by InternalBreakpointId rather than BreakpointId That means we need to do some more work when setting a breakpoint. Specifically, we need to figure out the internal ids (occurrences of a breakpoint) from the source-level BreakpointId we want to set the breakpoint at (recall :break refers to breaks at the source level). Besides this change being an improvement to the handling of breakpoints (it's clearer to have a single unique identifier than two competing ones), it unlocks the possibility of generating "internal" breakpoints during Cg (needed for #26042). It should also be easier to introduce multi-threaded-aware `BreakArrays` following this change (needed for #26064). Se also the new Note [ModBreaks vs InternalModBreaks] On i386-linux: ------------------------- Metric Decrease: interpreter_steplocal ------------------------- - - - - - bf03bbaa by Simon Hengel at 2025-08-01T04:39:05-04:00 Don't use MCDiagnostic for `ghcExit` This changes the error message of `ghcExit` from ``` <no location info>: error: Compilation had errors ``` to ``` Compilation had errors ``` - - - - - a889ec75 by Simon Hengel at 2025-08-01T04:39:05-04:00 Respect `-fdiagnostics-as-json` for driver diagnostics (see #24113) - - - - - 81577fe7 by Ben Gamari at 2025-08-02T04:29:39-04:00 configure: Allow override of CrossCompiling As noted in #26236, the current inference logic is a bit simplistic. In particular, there are many cases (e.g. building for a new libc) where the target and host triples may differ yet we are still able to run the produced artifacts as native code. Closes #26236. - - - - - 01136779 by Andreas Klebinger at 2025-08-02T04:30:20-04:00 rts: Support COFF BigObj files in archives. - - - - - 1f9e4f54 by Stephen Morgan at 2025-08-03T15:14:08+10:00 refactor: Modify Data.List.sortOn to use (>) instead of compare. (#26184) This lets a more efficient (>) operation be used if one exists. This is technically a breaking change for malformed Ord instances, where x > y is not equivalent to compare x y == GT. Discussed by the CLC in issue #332: https://github.com/haskell/core-libraries-committee/issues/332 - - - - - 4f6bc9cf by fendor at 2025-08-04T17:50:06-04:00 Revert "base: Expose Backtraces constructor and fields" This reverts commit 17db44c5b32fff82ea988fa4f1a233d1a27bdf57. - - - - - 937c41d5 by Matthew Pickering at 2025-08-05T14:05:35+01:00 level imports: Check the level of exported identifiers The level imports specification states that exported identifiers have to be at level 0. This patch adds the requird level checks that all explicitly mentioned identifiers occur at level 0. For implicit export specifications (T(..) and module B), only level 0 identifiers are selected for re-export. ghc-proposal: https://github.com/ghc-proposals/ghc-proposals/pull/705 Fixes #26090 - - - - - 148 changed files: - compiler/GHC/ByteCode/Asm.hs - compiler/GHC/ByteCode/Breakpoints.hs - compiler/GHC/ByteCode/Instr.hs - compiler/GHC/ByteCode/Linker.hs - compiler/GHC/ByteCode/Types.hs - compiler/GHC/Core.hs - compiler/GHC/Core/FVs.hs - compiler/GHC/Core/Make.hs - compiler/GHC/Core/Opt/Arity.hs - compiler/GHC/Core/Opt/CprAnal.hs - compiler/GHC/Core/Opt/Monad.hs - compiler/GHC/Core/Opt/SpecConstr.hs - compiler/GHC/Core/Opt/Specialise.hs - compiler/GHC/Core/Opt/WorkWrap/Utils.hs - compiler/GHC/Core/Predicate.hs - compiler/GHC/Core/Rules.hs - compiler/GHC/Core/Subst.hs - compiler/GHC/Core/TyCo/Rep.hs - compiler/GHC/Core/Unfold/Make.hs - compiler/GHC/Core/Utils.hs - compiler/GHC/CoreToIface.hs - compiler/GHC/Driver/CmdLine.hs - compiler/GHC/Driver/Make.hs - compiler/GHC/HsToCore/Binds.hs - compiler/GHC/HsToCore/Breakpoints.hs - compiler/GHC/HsToCore/Errors/Ppr.hs - compiler/GHC/HsToCore/Pmc/Solver/Types.hs - compiler/GHC/Iface/Ext/Ast.hs - compiler/GHC/Linker/Loader.hs - compiler/GHC/Runtime/Debugger/Breakpoints.hs - compiler/GHC/Runtime/Eval.hs - compiler/GHC/Runtime/Interpreter.hs - compiler/GHC/StgToByteCode.hs - compiler/GHC/SysTools/Tasks.hs - compiler/GHC/Tc/Deriv.hs - compiler/GHC/Tc/Deriv/Infer.hs - compiler/GHC/Tc/Deriv/Utils.hs - compiler/GHC/Tc/Errors.hs - compiler/GHC/Tc/Errors/Ppr.hs - compiler/GHC/Tc/Gen/App.hs - compiler/GHC/Tc/Gen/Export.hs - compiler/GHC/Tc/Gen/Expr.hs - compiler/GHC/Tc/Gen/Pat.hs - compiler/GHC/Tc/Gen/Sig.hs - compiler/GHC/Tc/Solver.hs - compiler/GHC/Tc/Solver/Default.hs - compiler/GHC/Tc/Solver/Dict.hs - compiler/GHC/Tc/Solver/Equality.hs - compiler/GHC/Tc/Solver/InertSet.hs - compiler/GHC/Tc/Solver/Monad.hs - compiler/GHC/Tc/Solver/Rewrite.hs - compiler/GHC/Tc/Solver/Solve.hs - + compiler/GHC/Tc/Solver/Solve.hs-boot - compiler/GHC/Tc/Solver/Types.hs - compiler/GHC/Tc/TyCl/PatSyn.hs - compiler/GHC/Tc/Types/Constraint.hs - compiler/GHC/Tc/Types/Evidence.hs - compiler/GHC/Tc/Types/Origin.hs - compiler/GHC/Tc/Utils/Monad.hs - compiler/GHC/Tc/Utils/TcMType.hs - compiler/GHC/Tc/Utils/TcType.hs - compiler/GHC/Tc/Utils/Unify.hs - compiler/GHC/Tc/Validity.hs - compiler/GHC/Tc/Zonk/Type.hs - compiler/GHC/Types/Name/Reader.hs - compiler/GHC/Types/Var.hs - compiler/GHC/Utils/Error.hs - configure.ac - docs/users_guide/runtime_control.rst - docs/users_guide/win32-dlls.rst - ghc/GHCi/UI.hs - ghc/GHCi/UI/Monad.hs - libraries/base/changelog.md - libraries/base/src/Control/Exception/Backtrace.hs - libraries/base/src/Data/List/NonEmpty.hs - libraries/ghc-internal/src/GHC/Internal/Data/OldList.hs - libraries/ghci/GHCi/Debugger.hs - libraries/ghci/GHCi/Message.hs - libraries/ghci/GHCi/Run.hs - rts/Disassembler.c - rts/Exception.cmm - rts/Interpreter.c - rts/PrimOps.cmm - rts/RaiseAsync.c - rts/RtsFlags.c - rts/STM.c - rts/Timer.c - rts/include/rts/Flags.h - rts/linker/LoadArchive.c - testsuite/tests/corelint/T21115b.stderr - + testsuite/tests/cpranal/sigs/T25944.hs - + testsuite/tests/cpranal/sigs/T25944.stderr - testsuite/tests/cpranal/sigs/all.T - testsuite/tests/deriving/should_compile/T20815.hs - testsuite/tests/deriving/should_fail/T12768.stderr - testsuite/tests/deriving/should_fail/T1496.stderr - testsuite/tests/deriving/should_fail/T5498.stderr - testsuite/tests/deriving/should_fail/T7148.stderr - testsuite/tests/deriving/should_fail/T7148a.stderr - testsuite/tests/hiefile/should_run/HieQueries.stdout - testsuite/tests/impredicative/T17332.stderr - testsuite/tests/interface-stability/base-exports.stdout - testsuite/tests/interface-stability/base-exports.stdout-javascript-unknown-ghcjs - testsuite/tests/interface-stability/base-exports.stdout-mingw32 - testsuite/tests/interface-stability/base-exports.stdout-ws-32 - + testsuite/tests/lib/stm/T26028.hs - + testsuite/tests/lib/stm/T26028.stdout - + testsuite/tests/lib/stm/all.T - testsuite/tests/quantified-constraints/T15290a.stderr - testsuite/tests/quantified-constraints/T19690.stderr - testsuite/tests/quantified-constraints/T19921.stderr - testsuite/tests/quantified-constraints/T21006.stderr - testsuite/tests/roles/should_fail/RolesIArray.stderr - testsuite/tests/rts/flags/all.T - + testsuite/tests/simplCore/should_compile/T26115.hs - + testsuite/tests/simplCore/should_compile/T26115.stderr - + testsuite/tests/simplCore/should_compile/T26116.hs - + testsuite/tests/simplCore/should_compile/T26116.stderr - + testsuite/tests/simplCore/should_compile/T26117.hs - + testsuite/tests/simplCore/should_compile/T26117.stderr - testsuite/tests/simplCore/should_compile/all.T - + testsuite/tests/splice-imports/DodgyLevelExport.hs - + testsuite/tests/splice-imports/DodgyLevelExport.stderr - + testsuite/tests/splice-imports/DodgyLevelExportA.hs - + testsuite/tests/splice-imports/LevelImportExports.hs - + testsuite/tests/splice-imports/LevelImportExports.stdout - + testsuite/tests/splice-imports/LevelImportExportsA.hs - testsuite/tests/splice-imports/Makefile - + testsuite/tests/splice-imports/ModuleExport.hs - + testsuite/tests/splice-imports/ModuleExport.stderr - + testsuite/tests/splice-imports/ModuleExportA.hs - + testsuite/tests/splice-imports/ModuleExportB.hs - + testsuite/tests/splice-imports/T26090.hs - + testsuite/tests/splice-imports/T26090.stderr - + testsuite/tests/splice-imports/T26090A.hs - testsuite/tests/splice-imports/all.T - testsuite/tests/typecheck/should_compile/T12427a.stderr - testsuite/tests/typecheck/should_compile/T23171.hs - testsuite/tests/typecheck/should_compile/TcSpecPragmas.stderr - testsuite/tests/typecheck/should_fail/T14605.hs - testsuite/tests/typecheck/should_fail/T14605.stderr - testsuite/tests/typecheck/should_fail/T15801.stderr - testsuite/tests/typecheck/should_fail/T18640a.stderr - testsuite/tests/typecheck/should_fail/T18640b.stderr - testsuite/tests/typecheck/should_fail/T19627.stderr - testsuite/tests/typecheck/should_fail/T21530b.stderr - testsuite/tests/typecheck/should_fail/T22912.stderr - testsuite/tests/typecheck/should_fail/tcfail174.stderr The diff was not included because it is too large. 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